A possible link between olfaction and miscarriage

Abstract

Unexplained repeated pregnancy loss is associated with an altered perception of male odors and differences in brain regions that process smells.

Keywords: Bruce effect; human; miscarriage; neuroscience; olfaction; pregnancy block; repeated pregnancy loss; social chemosignaling.

Figure 1.. Differences in how women who have experienced unexplained repeated pregnancy loss (uRPL) and women without the condition perceive odors, and how their brains process them.

(A) A group of women who have experienced uRPL and a control group were exposed to three different odors: a blank odor; the odor of their spouse; and a non-spouse odor. The number of women in the control group able to identify their partner’s odor could be explained by chance; the number of women in the uRPL group able to identify their partner’s odor was significantly higher. (B) Exposure to subliminal levels of male body odor while watching arousing movie clips elicits increased activity in the hypothalamus of women in the uRPL group (indicated in red; right), whereas hypothalamic activity decreases slightly in the control group (pale blue; left). Women in the uRPL group also had smaller olfactory bulbs. However, the precise links between altered olfactory processing in the brain and miscarriage are not yet fully understood.